Ignition breaker points



@at I7, T1967 .1. F. PENROSE IGNITION BREAKER POINTS Filed Nov. 26, 1965 United States Patent O 3,347,999 IGNITION BREAKER POINTS .lohn F. Penrose, 1027 12th St.,

Boulder, Colo. 80302 Filed Nov. 26, 1965, Ser. No. 509,851 8 Claims. (Cl. 200-30) ABSTRACT OF THE DISCLOSURE Ignition breaker points mounted in a cartridge type assembly with the movable contact carried on a reciprocating cylinder.

The present invention relates to the art of spark ignited internal combustion engines, and more particularly to improved ignition breaker points for `an automotive or the like engine.

Most breaker points in commercial use today comprise a frame or bracket mounted in the distributor of an engine and carrying a fixed contact or point, usually made of tungsten. An opposed movable contact also of tungsten is mounted on the end of :an arm pivoted on the frame or bracket. A spring acting between the bracket and the arm tends to hold the contacts or points in engagement. An adjacent cam in the distributor causes the arm to move against the force of its spring, thereby periodically opening the points or moving the contacts out of engagement in timed relation with the operation of the pistons and valves. In order for breaker points to operate eiciently, the contacting surfaces should be absolutely parallel so that there will be a surface engagement. If one of the contacts is tilted or canted relative to the other, then there is a line or point engagement, and the resulting localized burning of the contacts upon opening and closing and concomitant sparking thereof leads to inefficient operation. The burning increases the resistance of the contact points, thereby leading to a weaker sparkat the spark plugs, and it also causes a build-up of material on one of the breaker points, thereby altering the gap or maximum separation of the breaker points. This leads to incorrect spark timing and to weakened spark.

The prior art commercial breaker points, due to the pivotal mounting of the movable point, almost :always CIK present the contacting faces of the breaker points in less than absolutely parallel relationship. There is almost inevitably less than surface engagement, with resulting malfunctions as noted above. This requires more frequent tune ups of the engine and more frequent replacement of breaker points. With both material cost and labor costs increasing, this is obviously an undesirable situation.

It has been proposed heretofore that ignition contacts or breaker points should be mounted in a package or cartridge assembly with the part carrying the movable contact mounted for reciprocation rather than for pivoting y to provide a new and improved cartridge type of breaker point assembly which is commercially competitive with present commercial breaker points.

A further object of this invention is to provide a simple and positive mechanical connection for the actual contact elements or points.

3,347,999 Patented Oct. 17, 1967 Yet another object of this invention is to provide a superior and utterly simple insulation for the movable breaker point or contact.

AStill vanother object of the present invention is to provide a simple and positive means for adjusting the gap or spacing of the contacts when in open position.

It is further an object of the present invention to provide packaged or cartridge type breaker points which can be substituted for conventional breaker points in an automotive or the like distributor without modification to the distributor.

Other and further objects and advantages of the present invention will be apparent from the following description when taken in connection with accompanying drawings wherein:

FIG. 1 is a partial top or end view of a distributor incorporating the breaker points of the present invention;

FIG. 2 is a side view partially in axial section as taken along the lines 2 2 in FIG. 1;

FIG. 3 is an exploded perspective view of the breaker points;

FIG. 4 is an axial sectional view through the breaker points as taken substantially 'along the lines 4--4 in FIG. 5;

FIG. 5 isl an axial sectional view at right angles to FIG. 4 as taken substantially along the lines 5,-5 in FIG. 4;

and

FIG. 6 is a cross-sectional view =as taken substantially along the lines 6-6 in FIG. 4.

Referring now in greater particularity to the drawings, and rst to FIG. 1 there is shown in part a distributor 10 of conventional nature including a breaker plate 12 and a cam 14 mounted `on a cam shaft 16 for rotation therewith centrally of the breaker plate. The cam isshown as being octagonal, in accordance with the usual practice for eight cylinder engines. It will be understood that the number of sides or lobes on the cam depends on the number of cylinders, all as is known.

A breaker point unit 18 is mounted on the breaker plate, and includes a bracket 20 consisting primarily of a flat plate having slots 22 therein, by means of which the bracket 18 is mounted, screws 24 being received in the slots and threaded into tapped holes in the breaker plate. A right angle, generally centrally located flange 26 upstands from the bracket 20 and mounts a cart-ridge or package unit 28 including the breaker points, as hereinafter will be set forth. The bracket further includes a right Vangle edge flange 30 receiving a plastic block 32 having a screw 34 threaded therein. The screw serves as a. terminal for connection to the coil and to the condenser, and also is connected by means of a wire 36 to the breaker point cartridge unit as hereinafter will be brought out.

The breaker point cartridge unit 28 is best seen in FIGS. 3-6, and includes a threaded thimble or cylinder 38 having a wall with external threads 40 thereon, and having a arrge 42 at one end (the end toward the cam). A relatively thin nut 44 is threaded on the threads 40 and lits against the flange 26, on the side thereof toward the cam. A similar nut 46 is threaded onto the threads 40' on the opposite side of the flange 26 and holds the thimble in mounted position.

The thimble 38 is hollow, having a central bore or passage 48 extending completely therethrough, and further having diametrically disposed longitudinal slots 50 opening at the end opposite the flange 42 to at least partially define a passage extending vtransversely to the boreV or passage 48. v

The breaker point cartridge further includes a reciprocable cylinder or carriage 52 mounted within the bore 48 of the thimble 38 and protruding from either end thereof. At the radially inner end the cylinder or carriage S2 is 3 provided with a transverse dove-tail slot S4 receiving a complementary dove-tail 56 of a wedge shaped cam follower 58 which rides against the `cam 14, as may be seen in FIG. 1. The plastic may be of any suitable type, such as the phenolic often used in breaker 'point con-'struction, either with or Without fiber reinforcement, or it may be one of the more modern plastics such as nylon.

The cylinder or carriage 52 h'as a transverse slot or window 60 completely therethrough `adjacent the end opposite the cam follower 58. The slot or window is rectangular in shape, and is closed at the top or remote end by an integral head 62. The head 62 is drilled diametric'all'y at 64, and the cylindrical hole thu's formed receives a Wire or `rodl 66 of suitable .contact or breaker point material, such as tungsten. As will be apparent, the ro'd or wire 66 is ground fiat at along a chord thereof to provide a nat contacting surface 63, tlie rod 66 thereby comprising the movable .breaker point or contact. As will be seen particularly in FIG. the contact 66 is embedded somewhat more than a ra'dial depth, whereby it is securely trapped in place. Thus, additional brazing or soldering is preferably used only for stability, although even this can be dispensed with when a suitable press fit of the rod is made in' the drilled bore or recess 64. It will be obvious that the contact 66 is in good electrical engagement with the recip'rocable cylinder 52. The latter is electrically connected to the thimble 38, and graphite preferably is pro'- vided between the cylinder 52 and thimble 38, :both as a lubricant and to provide improved electrical contact. The thimble 38 is grounded to the bracket 20, and hence to the lbreaker plate 12. The cylinder 52 is provided with a central bore 70 leading from the cam follower 58 to the window 60. A helical spring 72 is mounted within the bore and bears at the radially outer end against structure shortly hereinafter to ,be described. At the radially inner end the spring 72 bears against a headless vset screw 74 threaded into internal 'threads 76 in the bore 70. The set screw allows vthe force exerted by the spring 72 to be adjusted in accordance with operational requirements of the breaker point unit. For example, higher spring force is desirable with extremely high speed engine operation, but is not necessary at lower speeds.

A fixed ineens including a contact mounting block 78 is mounted in the window 60 and comprises a large central bed 80 transversely drilled along its radially outer surface at 82 and receiving a contact or breaker point Wire or rod 84 having a flattened surface 86 substantially perfectly parallel to the, breaker 'point surface 68 'and urged into engagement therewith by the spring 72. The contact mounting block 78 further includes a base or slab portion integral with the bed ,'80 and including a Snort end 86 extending from one end of the bed 80 (down, in FIG. 4), and a longer slab end 'or table portion 88 vextending from vthe opposite end olf the bed (up, in FIG. 4). The slab or table ends 86 and 8'8 extend through the slots 50 in the thimble 38, and thus are guided by the edges of the slot. The outer end of 'the longer arm or end 88 is provided with an aperture 90 through which the wire 36 extends and is soldered in place. Obviously, the aperture could be threaded for receipt of a screw to avoid the use 'of solder.

Since the breaker point or contact 66 is grounded, it is obvious that the breaker Apoint or contact 84 must not be grounded. Accordingly, the mounting block 78 is insulated, and the insulation comprises a semi-rigid but fol'dable sheet of insulating material 92, perhaps seen best in FIG. 3. The insulating material initially is in a channel shape, comprising a bight 94 which lies beneath the mounting blocks 78 substantially throughout its transverse length. It also includes side flanges 96 which lie alongside the mounting block. The side flanges are provided near their ends with slits or cuts 98, and the adjacent material is folded over the tops of the arms 86 Aand 88 as indicated at 100.

A sheet metal shim 102 is trapped between the contact mounting block 78' and the nut 46 and4 forms a base for the spring 72. A nut 104 is threaded onto the threads 4d of the thimble 38 and clamps the arms 86 and 88 of the contact mounting block against insulation and hence against the shim 102 and the nut 46. The insulation 92 engages the nut 46 and the nut 104, and other adjacent parts whereby to insulate the contact mounting block therefrom.

It will now be seen that the spring 72 holds the cylinder 52 radially in toward the cam with the surfaces 68 and 86 of the contacts 66 and 84 in engagement. When the lobes of the cam 14 raise the cam follower 58 the cylinder 52 is forced radially outward. This moves the contact 66 away from the'contact 84, and causes a collapsing field in the ignition coil, in accordance with conventional practice, whereby to provide the necessary spark for the spark plugs. It will be apparent that the cylinder 52 moves with a reciprocating motion along a straight line, whereby it is a simple matter to machine the surfaces 68 and 86 for initial parallelism which will at all times be maintained. The length of the contacts 66 and 84 insures adequate surface area for contact engagement to avoid unduly high current densities which would cause burning of the surfaces.

It will be apparent that the gap to which the contacts can be opened can be adjusted by threading the nuts 44, 46 and 104 along the threads 40 of the thim'ble 38.

The two contacts are securely held in their respective mounting portions -by means of the cylindrical shape and embedrnen't greater than a radius. The particular mounting block for the fixed contact and its position relative to the other parts not only insures precise positioning of the fixed contact, but also provides for ready electrical connection thereto, and for simple and inexpensive insulation thereof.

The specific example of the invention as herein shown and disclosed will be understood as being for illustrative purposes. Various changes in structure Will no doubt occur to those skilled in the art, and will be understood as forming a part of the present invention insofar as they fall vwithin the spirit and scope of the appended claims.

The invention is claimed as follows:

1. An ignition breaker point assembly for use in the distributor of an internal combustion engine said breaker point assembly comprising: a base means for mounting the breaker point assembly radially outwardly of a cam in the distributor of an engine, said base means at least partially defining a first passage and a second passage eX- tending transversely to and intersecting said first passage; a carriage member mounted in said first passage for reciprocation relative to said base means, said carriage member at least partially defining a slot located adjacent to a first end portion of said carriage member; a cam follower mcans mounted on a second end portion of said carriage member for engaging the cam of a distributor to reciprocate said carriage member relative to said base means as the cam is rotated during operation of the engine; lfirst contact means iixedly mounted on an outer end portion of the slot in said carriage member for movement relative to said lbase means when said carriage member is reciprocated by rotation of said cam means; second contact means connected to 'said base means and extending 'through `the first and second passages in said base means into the slot in said carriage member for engagement with 'said first contact means; and spring means engaging said carriage member for urging said carriage member into a first position in which said first contact means is in engagement with said second contact means to interconnect ignition circuitry for the engine, said car-- in claim 1 wherein: the slot in said carriage member eX- tends through said carriage mem-ber and said second contact means extends through the slot for supporting engagement with said base means on opposite sides of said carriage member.

3. An ignition point assembly as set forth in claim 1 wherein: said rst and second contact means have confronting flat chordal surfaces which are positioned in abutting engagement when said carriage member is in the rst position.

4. An ignition breaker point assembly as set forth in claim 1 further including: adjustment means for selectively varying a force exerted by said spring means against said carriage member to urge said carriage member into the first position.

S. An ignition breaker point assembly as set forth in claim 1 further including: adjustment means for moving said base means radially relative to a cam of a distributor to adjust the distance through which said carriage member is reciprocated by rotation of the cam.

6. An ignition breaker point assembly as set forth in claim 1 wherein: the second passage in said base means is formed by a pair of slots extending inwardly from an end portion of said base means, said slots in said base means being in radial alignment with the slot in said carriage member.

7. An ignition breaker point assembly as set forth in claim 1 wherein: said spring means is mounted within a central bore in said carriage member and exerts a force against said second contact means to urge said carriage member into the first position.

8. An ignition breaker point assembly as set forth in claim 7 further including: insulation means positioned `between said spring means and said second contact means for electrically insulating said spring means from said second contact means.

References Cited UNITED STATES PATENTS 6/1954 Randol 20G-30 6/1962 Sargis 200--30 

1. AN IGNITION BREAKER POINT ASSEMBLY FOR USE IN THE DISTRIBUTOR OF AN INTERNAL COMBUSTION ENGINE SAID BREAKER POINT ASSEMBLY COMPRISING: A BASE MEANS FOR MOUNTING THE BREAKER POINT ASSEMBLY RADIALLY OUTWARDLY OF A CAM IN THE DISTRIBUTOR OR AN ENGINE, SAID BASE MEANS AT LEAST PARTIALLY DEFINING A FIRST PASSAGE AND A SECOND PASSAGE EXTENDING TRANSVERSELY TO AND INTERSECTING SAID FIRST PASSAGE; A CARRIAGE MEMBER MOUNTED IN SAID FIRST PASSAGE FOR RECIPROCATION RELATIVE TO SAID BASE MEANS, SAID CARRIAGE MEMBER AT LEAST PARTIALLY DEFININF A SLOT LOCATED ADJACENT TO A FIRST END PORTION OF SAID CARRIAGE MEMBER; A CAM FOLLOWER MEANS MOUNTED TO A SECOND END PORTION OF SAID CARRIAGE MEMBER FOR ENGAGING THE CAM OF A DISTRIBUTOR TO RECIPROCATE SAID CARRIAGE MEMBER RELATIVE TO SAID BASE MEANS AS THE CAM IS ROTATED DURING OPERATION OF THE ENGINE; FIRST CONTACT MEANS FIXEDLY MOUNTED ON AN OUTER END PORTION OF THE SLOT IN SAID CARRIAGE MEMBER FOR MOVEMENT RELATIVE TO SAID BASE MEANS WHEN SAID CARRIAGE MEMBER IS RECIPROCATED BY ROTATION OF SAID CAM MEANS; SECOND CONTACT MEANS CONNECTED TO SAID BASE MEANS AND EXTENDING THROUGH THE FIRST AND SECOND PASSAGES IN SAID BASE MEANS INTO THE SLOT IN SAID CARRIAGE MEMBER FOR ENGAGEMENT WITH SAID FIRST CONTACT MEANS; AND SPRING MEANS ENGAGING SAID CARRIAGE MEMBER FOR URGING SAID CARRIAGE MEMBER INTO A FIRST POSITION IN WHICH SAID FIRST CONTACT MEANS IS IN ENGAGEMENT WITH SAID SECOND CONTACT MEANS TO INTERCONNECT IGNITION CIRCUITRY FOR THE ENGINE, SAID CARRIAGE MEMBER BEING MOVABLE IN SAID FIRST PASSAGE AGAINST THE URGING OF SAID SPRING MEANS TO MOVE SAID FIRST AND SECOND CONTACT MEANS INTO A SPACED APART RELATIONSHIP TO INTERRUPT THE IGNITION CIRCUITRY FOR THE ENGINE. 